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• Matricaria discoidea

Matricaria discoidea — rayless chamomile

Facts

Rayless chamomile is native to northwestern North America and has spread eastward and to Europe. It was used by Native Americans as a medicinal and aromatic plant. Another common name is pineapple weed, which refers to the shape and smell of the flower heads.

Habitat

Anthropogenic (man-made or disturbed habitats)

Characteristics

• Flowers

  Bases of bract appendages

  NA

  Bract color

  the bracts are not colored or tinged with pink, red or purple

  Bract cycle number

  there are three or more cycles of bracts

  Bract inner side hairs

  the bracts are not hairy on their inner surfaces

  Bract keels

  the bracts do not have keels

  Bract margins

  there are few or no fine hairs along the bract margins

  Bract outer side hair type

  the bracts are not hairy on their outer surface

  Bract outer side hairs

  the bracts are not hairy on their outer surfaces

  Bract separation

  the bracts appear completely unconnected to one another on all flower heads

  Bract shape

  the main bracts are oblong (roughly rectangular but rounded at the ends)

  Bract spines

  the bracts have no spines

  Bract texture

  the bracts have a similar texture to a leaf

  Bract tip extension appearance

  NA

  Bract tip extension edge

  there are no projections from the bract tips

  Bract tip orientation

  the bracts are pressed against the plant, or spreading out at the tips

  Bracts

  the bracts in separate cycles are similar or gradually changing from the outer to inner cycles

  Disk flower color

  • green to brown
  • yellow

  Disk flower lobe number

  4

  Disk flower number

  more than 50

  Disk flower reproductive parts

  the disk flower has both pollen- and seed-producing parts

  Disk width

  4–10 mm

  Flower head number

  • each flowering stem has four or more flower heads on it
  • each flowering stem has only one to three flower heads on it

  Flower head outer flowers

  at the outer edge of the flower head, the flowers have no enlarged lobe or strap, and are of similar size as those in the center of the disk

  Flower head platform

  the base has no bristles or papery scales

  Flower head platform surface

  NA

  Flower head position

  each of the flower heads is separate on its own peduncle (stalk), not clustered in groups

  Flower head profile

  the disk is conical across the top

  Flower type in flower heads

  the flower head has disk flowers only, and lacks the strap-shaped flowers

  Height of flower head base

  2.5–3.8 mm

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  • the inflorescence is flat-topped in profile
  • the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others

  Inflorescence stem

  the stem of the inflorescence is not hairy

  Number of bracts at flower head base

  29–47

  Ovary cross-section

  the ovary is compressed (flattened)

  Ovary hair type

  the ovary has no hairs on it

  Ovary hairs

  the ovary has no hairs on it

  Ovary lines or ribs

  • there are four to six lines or ribs visible on the ovary
  • there are three lines or ribs visible on the ovary

  Peduncle hair type

  the hairs on the peduncles are simple (not branched), don’t have glands, and are not woolly

  Peduncle hairs

  • the peduncles are hairy
  • the peduncles have no hairs

  Peduncle length

  2–30 mm

  Peduncle orientation

  the flower heads are held upright, or slightly angled outwards

  Ray flower color

  NA

  Ray flower reproductive parts

  NA

  Ray flowers

  0

  Ray length

  0 mm

  Reproductive system

  all the flowers on the plant contain both carpels and stamens

  Scale tip

  NA

  Smaller bracts at base of bracts

  there is a cycle of much smaller bracts outside the cycle of larger and longer bracts

  Style branches

  the style branch is wider at the tip and has a flattened end, or the style branches are wider at the tips and have flattened ends

• Fruits or seeds

  Number of pappus parts

  1

  Ovary length in developed fruit

  1.15–1.5 mm

  Seed hair tuft bases

  NA

  Seed hair tuft color

  NA

  Seed hair tuft details

  NA

  Seed hair tuft tips

  NA

  Seed hairs uniform

  NA

  Seed tuft scale number

  0

  Seed tuft type

  the pappus is made of a circle or rim of lobes or teeth on the ovary

  Top of disk flower ovary

  NA

  Tuft or plume on fruit

  there is no plume, or the plume is made up of scales, awns, a crown, or a rim

• Glands or sap

  Bract resin

  the bracts have no resin or resin glands

  Leaf blade glands

  the leaf blades have no glandular (translucent) dots or scales

  Ovary glands

  there are no visible glands on the ovary

  Sap

  the sap is clear and watery

• Growth form

  Growth form

  the plant has one or more free-standing stems

  Horizontal rooting stem

  there are no stolons

  Plant lifespan

  the plant is annual, it lacks evidence of previous years' growth

  Spines on plant

  the plant has no spines

  Underground organs

  there is a thickened taproot on the plant

• Leaves

  Hairs on underside of leaf blade

  the underside of the leaf is not hairy, or has very few hairs

  Hairs on upper side of leaf blade

  the upper side of the leaf is not hairy, or has very few hairs

  Leaf arrangement

  alternate: there is one leaf per node along the stem

  Leaf blade base

  the leaf has no petiole

  Leaf blade base shape

  the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)

  Leaf blade bloom

  the underside of the leaf has no noticeable bloom

  Leaf blade edges

  • the edge of the leaf blade has lobes, or it has both teeth and lobes
  • the edge of the leaf blade has no teeth or lobes

  Leaf blade flatness

  the leaf is flat (planar) at the edges

  Leaf blade hairs

  NA

  Leaf blade length

  5–85 mm

  Leaf blade surface colors

  there is no noticeable color variation on the upper surface of the leaf

  Leaf blade veins

  the leaf blade has one main vein running from the base towards the tip

  Leaf blade width

  2–20 mm

  Leaf disposition

  the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem

  Leaf spines

  there are no spines on the leaf edges

  Leaf stalk

  the leaves have no leaf stalks, but attach directly to the stem

  Leaf stalk length

  0 mm

  Leaf tip extension

  NA

  Leaf tufts in axils

  there are clusters of smaller leaves growing out of axils

  Leaf type

  • leaves are compound (made up of two or more discrete leaflets)
  • leaves are simple (i.e., lobed or unlobed but not separated into leaflets)

  Specific leaf type

  • the leaf has a row of two or more lobes on each side of the central axis
  • the leaf has a row of two or more lobes on each side of the central axis, and each lobe itself has rows of lobes on each side of the lobe's central axis
  • the leaf is compound, there are two or more discrete leaflets

  Teeth per side of leaf blade

  0

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  man-made or disturbed habitats

• Scent

  Plant odor

  • the plant has a pleasant odor, such as licorice, fruit or resin
  • the plant has an unpleasant or repellant odor

• Stem, shoot, branch

  Flowering stem cross-section

  the flowering stem is circular, or with lots of small angles

  Leaves on stem

  there is at least one full leaf above the base of the flowering stem

  Stem bloom

  there is no powdery or waxy film on the stem

  Stem internode hair direction

  NA

  Stem internode hair length

  0 mm

  Stem internode hair type

  the stem has no hairs between the nodes

  Stem internode hairs

  the stem has no hairs between the nodes

  Stem wings

  the stem does not have wings on it

Wetland status

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae